In current communications networks, when session initiation protocol (SIP) messages are used in association with a session or event, accounting information is typically generated so that appropriate billing records may be created. In addition, various downstream applications may examine the billing records for purposes such as billing verification, fraud detection, revenue assurance and data analysis.
For example, SIP messaging may be used in an Internet protocol (IP) multimedia subsystem (IMS) environment, for instant messaging (IM), voice-over-IP (VoIP), and other IP-based telephony solutions. In an IMS environment, accounting information may be generated by a network entity (NE) such as a short message service center (SMSC) upon the delivery or receipt of a short message service (SMS) message. This accounting information may include information extracted from SIP messages, as well as other accounting-related data, and may be passed to a function for converting the accounting information into a format called a charging detail record (CDR). The CDR may then be sent to a billing system, where it may be used to bill the subscriber for the session or event.
One problem associated with current SIP charging and verification systems is that they are susceptible to fraud. In one exemplary scenario, so-called “fraudsters” may exploit an aspect of conventional charging systems in order to defraud network operators. Typically, network entities such as SMSCs are responsible for both delivering messages to subscribers and for generating accounting information associated with the charging event (i.e. message delivery). In an online billing scenario, also referred to as prepaid billing, before delivering a message to a particular subscriber, the message may be cached while a prepaid application is queried to determine whether the subscriber has enough prepaid credit to deliver the message. However, the message volume associated with SMSCs is often so large that the SMSC cannot query the prepaid application without risking congestion or failure of the SMSC. Therefore, SMSCs may prioritize delivery of messages over querying the prepaid application or generating accounting information. In short, an overloaded SMSC may assume that a subscriber possesses enough prepaid credit to send the message and prevents congestion by not querying the prepaid application and not generating accounting information. Fraudsters may abuse this aspect of conventional charging systems to defraud network operators. They may begin by purchasing a prepaid card containing a small number of prepaid credit and attempt to send a large volume of messages such that the SMSC becomes overloaded and employs the procedures described above where each message attempt is delivered without validating the subscriber's prepaid credit amount or generating accounting information associated with the messages. Accordingly, downstream applications, such as billing verification applications, may not receive an indication that the fraud has occurred until it is too late. This can leave network operators with numerous and expensive uncollectible bills.
Another problem associated with current SIP charging and verification systems is that they are prone to error. For example, because billing systems are typically located downstream from the various network entities and applications involved in producing accounting information, data corruption may accumulate and hinder verification systems' ability to accurately audit SIP transactions. Therefore, even when accounting information is generated, by the time it has been examined and/or converted into additional formats it may include missing or incomplete data. This may produce inaccurate or under-billed records that cost network operators to correct.
Yet another problem associated with current SIP charging and verification systems is that they lack a redundant audit trail. In the event that accounting information is corrupted, incomplete, or not generated as described above, current verification systems lack the ability to correct corrupted data, complete incomplete records, or recreate missing information. They also lack the ability to tell network operators where in the information flow the error occurred so that it may be examined and corrected.
Accordingly, there exists a need for improved methods and systems for providing billing and usage data to downstream applications.